I am using VBA in Excel to create a Word document containing tables
from a spreadsheet. However, I often get an error message that pops
up: "The object is not responding because the source application may
be busy." When I stop the program at that point, I get the VBA error:
"Automation error - Call was rejected by callee."

Here is how I start Word:

Function StartWord() As Boolean
StartWord = False
' Try to open an existing instance of Word
On Error Resume Next
Set WordApp = GetObject(, "Word.Application")
On Error GoTo 0
' If Word is not started, start a new instance
If WordApp Is Nothing Then
Set WordApp = CreateObject("Word.Application")
End If
WordApp.Visible = False
StartWord = True
End Function

Here are the relevant code snippets that use Word:

' Start the Word application
If Not StartWord() Then
MsgBox "Unable to start Microsoft Word", vbCritical,
"Microsoft Word Error"
Exit Function
End If
' Add a new Word document
WordApp.Application.ScreenUpdating = False
WordApp.Documents.Add
'Set DataTableWS = DataWB.Sheets("table")
' Set up Word document properties
With WordApp.ActiveDocument.PageSetup
.Orientation = wdOrientPortrait
.TopMargin = 20
.BottomMargin = 20
.LeftMargin = 40
.RightMargin = 40
.PageWidth = 700
.PageHeight = 800
.Gutter = 0
End With

It consistently bombs on the statement:

With WordApp.ActiveDocument.PageSetup

Can anyone provide advice on this problem?

Thanks, Alan